fear_greed_index

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, but description adequately explains the tool returns a value and classification with optional history. It is clearly read-only and informational, so no hidden behaviors.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Concise description with all essential information: purpose, usage, return format, example, and cost. Front-loaded with the core definition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's simplicity (one optional param, no output schema), the description fully covers what the agent needs to know: what it does, when to use, what to expect, and cost.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% for the single 'limit' parameter. Description adds context by mentioning 'optional history' and showing history array in example, reinforcing the parameter's purpose.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it is the 'Crypto Fear & Greed Index' with range (0-100) and optional history. It is distinct from sibling tools like orderbook_depth or crypto_news.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly says 'Use when: You need to gauge overall crypto market sentiment or mood — whether the market is fearful or greedy.' Also provides example response and notes cost.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.